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Revision as of 08:52, 23 August 2012
Note: merge this article with electric vehicle to "Electric and hybrid vehicle"
The electric vehicle
A purely electric vehicle uses a large amount of batteries, combined with a electric motor. They emit no exhaust fumes whatsoever and are thus very useful in certain situations (ie use in enclosed spaces).
Downsides of the electric vehicles
Amount of battery capacity required
Purely electric vehicles require a great amount of battery capacity, and thus a huge amount of batteries. At present, lithium ion batteriesW are mostly used (sulpheric acid-lead batteries can be used too, but are generally not used anymore due to their low power/weight ratio). Lithium-ion batteries have a major environmental impact (the production of these batteries atleast, not their use).[verification needed]
Other battery types can also be used (some battery types lowers this impact greatly), but all generally still have a negative environmental effect, and weighten down the vehicle and reduce range (compared to fuel, batteries -regardless of the type- have very low power/weight ratio's.[1]
The hybrid vehicle as a solution to remove a lot of battery capacity
One solution to reducing the amount of battery capacity is to swap the battery with a (ultra)capacitor and a range extender (ie microturbine, IC (gasoline) engine, IC (diesel) engine or Stirling engine) fitted to a dynamo or alternator to recharge the ultracapacitor. This is known as a series hybrid.
Especially Stirling engines (which are 10% more efficient than IC (gasoline) engines, ie regarding incineration) are very useful in vehicles, as they are very light, and (as any range extender) allow to use of the energy dense fuels (more energy can be taken along compared to batteries).
The capacitor can be used as a buffer (so storing say energy to drive a few hundred meters upto 1 km, rather than storing energy for say 100 - 500 km).
Advantages of the hybrid electric to purely electric vehicles
Besides the main advantage of the descreased weight/increased range, and the advantage of eliminating a lot of battery capacity (which is useful as the production of the batteries are environmentally unfriendly), there are additional advantages:
- Unlike Stirling-only vehicles, Stirling-electric hybrid vehicles can be immediatelly driven after starting. Stirling engines require a "warm-up time", yet due to the capacitor, the vehicle can use the energy still present in the capacitor to immediatelly drive off. The capacitor is then continuously recharged underway.
- Stirling engines extract more energy and can use other environmentally friendly fuels (ie plant oils) than IC (gasoline) engines.
- It also still function as a hybrid (allowing to switch to the electric motor within densely populated areas). Electric motors are more efficient here than a heat engine since the heat engine (ie microturbine, IC engine or Stirling engine) would need to operate on a speed/load that is not optimal for it
- In the specific case of parallell hybrid electric vehicles fitted with a Diesel engine (not a gasoline engine as the latter are more efficient on operating on almost any speed/load ratio):
- Diesel engines can not oxygenate their fuel optimally beyond a certain speed/load[2] (it works fine for low speeds/loads though). This results in a lesser energy conversion and thus power loss. The electricity generator (dynamo or alternator) too works more efficient[3] at a specific speed and load. As with series hybrids it's possible to keep the speed/load of both the diesel engine and the electricity generator at a constant rate, near their optimal speed/load range, the efficiency is kept very high during the entire trajectory the vehicle needs to cover.
Additional improvements to electric vehicles
Plug-in hybrids
Plug-in hybridsW are series or parallell hybrids equipped with a power plug. They have the option of recharging the batteries from the mains electricity grid. The cost of electricity to power plug-in hybrids during all-electric operation in California in 2007 has been estimated as less than one fourth the cost of gasoline.[4]
Criticisms
Art Spinella of CNW Marketing has released reports critical of hybrids, particularly their claim of economic benefits, though this analysis is based on certain doubtful assumptions about the lifespan of hybrids.[5] One widely-released report in 2005, the in-depth Dust-to-Dust study (from production to disposal of a vehicle) found that hybrids fared worse than large SUVs. In particular, a Toyota Prius cost $3.24/mile to build, operate and dispose/recycle, whereas a Chevy Tahoe or GMC Yukon cost $2.93/mile. (For comparison purposes, a Hummer H3 was $2.065/mile, an Audi A6 was $4.96/mile, a Toyota Echo was $.70/mile and a Jeep Wrangler was $.60/mile. Other hybrids were roughly similar to the Prius, the Honda Insight was the best at $2.94/mile). However, these numbers are not without dispute. The CNW report estimated that a Prius cost $354,000 over its lifetime of 109,000 miles, and a Chevy Tahoe cost $787,000 over 268,000 miles and a Ford Excursion cost a whopping $888,000 over 269,000 miles. There are two issues with this - the simpler one being that a Prius may have an average lifespan of much more than 109,000 miles - and in fact the batteries have a 10 year, 150,000 mile warranty.[6] It is a recently introduced car, but several incidental cases of the Prius operating more than 200,000 miles on the original batteries have been reported. Assuming an industry-average lifespan of 178,000 miles, the Prius would then only cost $2.28/mile, beating all large SUVs and full-size pickups.
Claims have been made that the batteries of the Prius have a very short lifespan, resulting in very high environmental impact for the distance traveled. In fact, the batteries have a 10 year, 150,000 mile warranty.[6]
Lifetime cost
The second issue is the lifetime cost of a vehicle.
A January 2007 analysis by Intellichoice.com calculated that all 22 currently available hybrids would save their owners money over a five year period. The Toyota Prius led the results with a five year cost of ownership 40.3% lower than comparable non-hybrid vehicles.[7] The CNW report reached different conclusions, but with some apparently faulty calculations.
Operating costs are fairly well-known, limited largely to fuel, repairs and maintenance. The initial buyer of the vehicle must pay for the mining, manufacturing, assembly, design and overhead of all components of the vehicle (assuming there is no massive government subsidy common to all industrialized nations). Otherwise the manufacturer or suppliers would be losing large sums of money on each vehicle (many times the price of the vehicle, given the numbers in this report) and quickly go out of business. Since little money changes hands when a car is junked, it is reasonable to assume the disposal of a vehicle is largely paid for by recyclable material (and to some extent, government-subsidized landfills). The CNW report shows large sums of money for each step in the process. Even the cost of transportation of workers to the workplace is covered, although that should be paid by their paycheck. Only government-subsidized road repair seems to be missing in the list of costs (which is affected more by multi-ton vehicles). The large dust-to-dust report does not get into specifics on how double-charging of expenses is avoided (such as steel that is recycled, or workers' costs and their salaries), but a detailed analysis of the whole report is not possible here. Briefly, without the bankruptcy of multiple nations and car manufacturers, the large figures associated with lifetime vehicle costs are highly suspect.
In any case, the less publicized but more recent report for 2006 vehicles (summarizing spreadsheets available only) has adjusted the figures considerably. According to CNW Marketing, hybrids now cost less per mile than large SUVs: the 2006 Prius is reported at $2.87/mile, Chevy Tahoe is $3.76/mile, and Ford Excursion is $4.04/mile. Regardless, until the vehicle lifetime costs can be verified more completely, and considering the inconsistency between claim short lifetime of the battery with the actual warranty period, these reports should be considered with skepticism - though of course some of their analysis may well be valid.
Suggested projects
- Check Reason.org's analysis and attempt to give an objective analysis of which cars are more efficient over their life cycle.[expansion needed]
This article or section contains content copied from the Hybrid electric vehicle page on Wikipedia.[8]
- We need to examine the relative environmental impacts, not the $ cost.--RichardB43 07:35, 26 January 2011 (PST)
Notes
- ↑ climate scientist Graeme Pearman's comments to Chriswaterguy (after his Lowy Institute talk, 18 Apr 2007) that he had helped to built a hybrid (15 years ago?) which did not use lithium ion batteries. (He confirmed my query as to whether this was the "Eco-Commodore," which I assume is actually the Holden ECOmmodore, but the ECOmmodore was much later, unveiled in 2000... was it just ignored for the intervening ~8 years? --Chriswaterguy)
- ↑ See wikipedia article on "Diesel engine"
- ↑ This difference can be quite high, ie brushed types can show a difference of 40% !
- ↑ HEV Center (2007) "What are Plug-In Hybrids?" Department of Mechanical and Aeronautical Engineering, UC Davis; retrieved 18 April 2007
- ↑ This report has been discussed also by the libertarian policy institute, the Reason Foundation - a public policy research organization based on "libertarian principles, including individual liberty, free markets, and the rule of law."[1] It is claimed that hybrids have a higher energy cost over their life cycle than normal cars, and even than the enormous Hummer.W This is calculated as dollars per mile. There are many factors, of which a significant one appears to be the assumption that a Hummer will last for three time as long, i.e. 300,000 miles instead of 100,000 miles for a Prius. Have You Hugged a Hummer Today?, Commentary, Reason.org, July 19, 2006
- ↑ 6.0 6.1 Prius Yes website (promotional website). Click "Prius Facts" for the statement about the warranty on the batteries.
- ↑ "Hybrids Cost-Efficient Over Long Haul", Business Week, January 9, 2007. The summary of the Intellichoice report is based on Wikipedia.
- ↑ The material section beginning "Art Spinella," was copied here 26 March 2007, with a note left on the Wikipedia talk page. It was quickly removed, as it contains considerable analysis and original research, which is suitable for Appropedia but not Wikipedia.
